Gear drive



Dec. 14, 1937. l M, R01-TER ZZG? GEAR DRIVE Filed July 51, 1936INVENTOR' ATToRNEw Patented Dec. 14, 193'?y UNITED l,stares 2,102,167GEAR DRIVE Busch-Sulzer Bros-Diesel Engine ,(o'mpany, St. Louis, Mo., acorporation of liiisfsoulfi application July s1, 19.3.6, seriaiNo.93,5537 4 fom-ms. (c1. 'x4-,411)

"The invention has reference to gear-coupled "crank-shafts' and `thelike and more particularly to the coupling gearing ywlsiereby twincrank- Yshafts -of combustion Yengines-maybe Aconnected to each otherand to a common .power take-.orf

although without limitation to any particular engine type. The object isto avoid, in a compact structure, the noise, wear and injurious Veiectresulting from thermal and kinetic distortions in such organizations andto maintain a substantially constant depth of mesh of the gear teeth ofthe coupling gear wheels under all conditions notwithstanding relativetemperature dilerences or uctuations and other causes.

The drawingv which is wholly diagrammatic will suice to illustrate theprinciples involved, Fig. 1 being in the plane of the shafts and Figs. 2and 3 details of the coupling. Y

'I'he two engine crank-shafts Irmay be understood to be the crank-shafts'of a twin-cylinder or opposed-piston engine or other type, bothjournalled in the engine frame 2, in bearings 3. The shafts are extendedthrough and beyond the bearings into connection with Oldham-typecouplings 4 through whichv they respectively VdriveV the toothed gearwheels 5. These gear wheels are geared to each other, eitherdirectly,'with the teeth of one intermeshing with those of the other, orotherwise and as usual in opposed-piston engines.

While the crank-shafts are journalled in the main frame 2 these gearwheels are journalled,

in a supplemental and independent frame or gear -support 6 and the twoframes are rigidly xed to The detail of the constructionjust referred tois not of consequence.Y vAn Oldham coupling, which is well known,comprises a terminal plate or iiange 8, in the present case tted to orformed on each crank shaft I`(Fig. 2), a floating disc 9 and acomplementary plate or flange IIJ secured to the hub of the connectedgear wheel. The iioating disc 9l is formed with radial ribs on itsopposite sides, rectangularly related, and registering withcorresponding grooves in the proximate end plates 8 and I0. It is alsoto be understood as having take-up springs, to prevent chattering, andother incidental coupling appurtenances not shown because well known.One of the gear wheels or one of the plates I0 is attached to the end ofa power take-off shaft Il for driving purposes. The supplemental frame 6is chambered at 12 V.to :accommodate .with gsome .clearance anyprojecting parts .of the `frame bearings 3 and its other cham-bersmay.acconnnodate watercircula- :tion ifldesired. When .bolted in `placeits-tubular .bosses 13, which ,sformltheibearings .ior the gear l wheelsv.5 are .practically in line with @the axes Qf the crank shafts. x

'Ihe distortion effects which have heretofore obstructed the mostefficient action of apparatus of this class are represented by thebending of the crank-shafts under the piston impulses, the lateraldisplacement of their axes incident to the running clearances which theyhave in their respective frame bearings 3; the change of the distancebetween such bearings which results from thermal expansion of the engineframe, ordinarily considerably hotter than the gear support, and theunequal change, from thermal effects, of the radii of the gear wheelsthemselves. While. the departures are individually not large, in theaggregate andat times, they are found to produce a considerable and veryobjectionable variationrin the depth of meshing of the gear teeth bywhich the twin shafts are connected, an objection always aggravated bythe use of aluminum alloys for the engine frame which alloys have highexpansion coefficients. By this invention and as exemplied in theconstruction above described, these departures are rendered ineffectualon the mechanical performance for the following reasons: Y

The symmetrical attachment of the main frame 2 and supplemental frame 6permits the latter to expand away fromV its point of bolt attachment,

independently of the expansion of the engine frame, so that the oneframe do-es not affect the other although the supplemental frame iscarriecl on the main frame. The gear wheels 5 are made of the samemetal, or of metal having the same expansion coefficient, as that of thesupplemental frame on which they are journalled and in consequence, suchexpansion, or contraction, as may occur in this frame with reference toits central bolting point 1, is compensated or neutralized by thecorresponding expansion or contraction, in the opposite direction, ofthe gear wheel radii with respect to their journal bearings I3, whichkeeps the gear teeth meshing to the same and proper depth leastproductive of wear, while any displacement of the crank-shafts, due toflexure or engine frame'expansion is inelective Y to modify thatcondition or aifect the bearing load by reasonof the interventionbetween them'and the wheels, of the laterally exible but torsionallyrigid couplings 4, In consequence of this combination and arrangementthe geared drive is smooth and quiet and also uniformly emcient underall conditions of use, and engines embodying this principle ofconstruction give better performance and are generally moresatisfactory.

I claim:

1. In a gear drive, the combination of twin shafts journalled in acommon frame, a toothed gear wheel aligned with and flexibly connectedto each of said shafts, a supplemental frame on which said wheels arejournalled, said frame being secured to the main frame at a pointintermediate of said shafts and Wheels, and each being free to expandindependently of the other in opposite directions from said point andsaid wheels having an expansion coeicient corresponding to that of thesupplemental frame adapted to neutralize the effect of its expansion.

2. In a gear drive, the combination of twin shafts journalled in a mainframe, a supplemental frame secured by its mid-point to a point on saidmain frame intermediate of said shafts, tubular bearing bosses on saidsupplemental frame surrounding said shafts, gear wheels on said bosses,flexible couplings between said shafts and said gear wheels, and a powertake-oi from one of said wheels.

3. In a gear drive, the combination of twin engine crank-shaftsjournalled in bearings on an engine frame and extended beyond saidbearings, gear wheels to which said shafts are connected, a supplementalframe secured to said engine frame at a point between said crank-shaftbearings and carrying journal bearings for said gear wheels, said framesbeing rigidly aixed to each other at a point symmetrically related tosaid shafts and to said wheels, a laterally flexible coupling betweeneach shaft and its gear and a power take-off from one of said gearWheels.

4. In a gear drive, the combination of twin engine crank shaftsjournalled in bearings in a common engine frame and extended beyond saidbearings, a supplemental frame secured to said engine frame at a pointintermediate of said shaft bearings and having tubular bossesrespectively surrounding the extended parts of said shafts, intermeshinggear wheels on said bosses having an expansion coefficient correspondingto the coefficient of said supplemental frame and flexible couplingsbetween said shafts and their associated gear Wheels.

MAX RO'I'I'ER.

